Automatic telephone system



March 14, 1933. M. MATHIAS AUTOMATIC TELEPHONE SYSTEM Filed March 31, 1952 Inuan To r maximi Han FER-Ia: MM

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Patented Mar. 14, 1933 UNITED STATES PATENT OFFICE Q AK'I'IENG TM 0! BERLIN, Gm, ASSIGNOR T0 & mnsxn OI m BERLIN, enmn AUTOIATIG TELEPHONE SYSTII Application fled larch 31, 1932, Serial No. 601187, and in Germany lay 89, 1981.

This invention relates to automatic'telephone systems in which connections of different value are set up. The ob'ect of the invention is to forcibly cut oil suc speaking connections which can be renewed at an time without loss of time and without extra charge, this being achieved by switching devices provided for limiting the duration of calls being caused to function by means which denote the value of the connections only when the lines are engaged for connections of low value.

An embodiment of the invention is shown in the drawing.

In this drawing a subscriber Tnl is shown to have access over a preselector V W, allocated to him, to a common group selector, for example IGW. The subscriber, by sending out impulses, is in a position to set this roup selector to-a further group selector, in example, HGW, and this latter device to a final selector, for example, LW. The subscriber T022 may then be reached by the transmission of two additional impulse series actuating the final selector LW.

The exchange is also provided witha time switch which serves the purpose of cutting ed the speaking connection after a definite time period.

All the speaking connections, however, are

not to be forcibly cut 03 but only those which the subscriber may set up again without any great loss of time. Connections which take a considerable time to complete (such as, for exam le, waiting for a toll call to be completed are not to be cut oil'.

Each individual subscriber in the embodiment is provided with a time switch for this purpose. Arrangements ma also be made to the efiect that this time switch is accessible to a large number of subscribers by, for example, associating the switch with the junction line.

The type of connections generally outlined above are in detail completed in the following manner: When the subscriber Tnl lifts his receiver, relay R is energized over: earth, battery, resistance Wil, contact 113, subscriber Tfll, contact 3t, relay R, earth. The closing of contact 171- sets up an impulse circuit for net D1, relay interrupter RUl, earth. The

y rotary magnet is intermittently influenced in this clrcut, causing the preselector to be advanced step by step until it reaches an idle succeeding group selector, for example, IGW. When this occurs the following circuit will be closed: earth, battery, d-wiper of the preselector VW, contact segment, contact 171' mdings II and I of relay T, c-wiper of Hit, rotary mag-.

the preselector VW, contacts 186, 20 0, 05- I normal contact 2170 of the group selector IGW, winding I of relays A and B earth. Belay T is energized in this circuit and brings the preselector to rest by opening its contact 16t. The locln'ng circuit for winding I of relay T is closed at contact '15t. In the above-mentioned circuit relays A and B also are energized and are maintained energized by means of their winding H over the subscribers line loop after contacts 2t and 4t have been closed. The short circuit for rela C is removed by the opening of contact 18 with the result that this relay is energized in the locking circuit for relay T and is made independent of the ofi-normal contact 21k of the group selector IGW due to the closing of contact 190. Relay C, in addition, actuates its contacts 28c. 35c, 40c, 41c, and 4410.

When the subscriber now transmits additional im ulses for the setting of the group sclector I W, that is to say, intermittently breaks the locking circuit for relays A and B, the vertical magnet H of the group selector IGW is intermittently energized accordingly and lifts the switch wipers of the group selector to the desired level. This energize ing circuit extends over: earth, contacts 26c, 28c, winding III of relay V, contact 32d of the rotary magnet D, rotary ofi-normal contact 33w of the group selector IGW, vertical magnet H, battery, earth. Relay V also is energized in this circuit and remains energized during the impulse series-since it operates as a slow acting relay due to the shortcircuit of its winding II. leased at the end of the impulse series with the result that the rotary magnet D is ener- Relay V is regized in the following circuit, the oil-normal contact 23k of the group selector IGW having been closed on the first vertical step: earth, battery, rotary magnet D, contact 220), off-normal contact 2370, contact 25p, earth. The grou selector moves one step and, by the closin 0 contact 31d causes winding I of rela Y V to be energized over the vertical magnet of the group selector which, however, is not energized during this operation. The rotary magnetof the group selector is re-energized when contact 2211 is opened, and therefore breaks the circuit of relay V at 31d.

Should the reached line be busy, the rotar magnet is re-energized after relay Vfallsbac and advances the group selectorafurther step. This interaction between relay V and the rotary magnet D continues until the group selector has reached an idle succeeding second group selector. Should this group selector happen to be the shown group selector IIGW, the following circuit is completed: earth, contacts 350, 36a, windings II and I of relay P, c-wiper of the group selector IGW, relay C1, battery, earth. Relays P and C1 are energized in this circuit. The closing of contact 37; causes the high resistance winding II of relay P to be short-circuited which thereby guards the group selector against further seizures. Contacts 42 and 4317 switch through the speaking leads to the group selector IIGlV.

The subscriber Tnl is now able to setthe second group selector IIGW in a manner of no interest in this case by transmitting an additional impulse series. This group selector IIGW then hunts for an idle final selector, for example LW. The subscriber can influence this also by sending out two impulse series and finally reach the required subscriber Tn2 over said final selector.

The speaking connection is thus completed between the subscribers T'nl and T'n2 after the appropriate switches have been set, ringing current applied, and the subscriber Tn2 has answered.

The time switch TS has, in the meantime, been caused to function due to the fact that the following circuit of relay B0 was closed when relay T was energized: earth, battery, relay B0, off-normal contact 13700 of the time switch, contact 1427, earth. Relay B0 is placed in a locking circuit independent of the above-mentioned off-normal contact due to the closing of contact 127m. The rotary magnet TS of the time switch is set to the contact bank of a 15-second switch by the actuation of contact 1160. Since the switch wiper of the 15-second switch comes into contact with the said contact every 15 seconds, the switch magnet TS of the time switch is accordingly energized every 15 seconds so that the time switch advances step by step at 15 seconds intervals. The time switch is provided with twenty-three contacts and takes about five minutes to complete one revolution. When the time switch reaches the last, that is to say, the 23rd contact osition, the off-normal contacts 57023 and 8 23 are closed. The closing of the off-normal contact 57023 is of no importance for the setting up of these connections. The oil-normal contact 87023 merel applies earth potential to the lower lead 0 the reselector VW. This causes windingII 0 relay B, in the group selector IGW, to be shortcircuited so that this relay releases and brings about the release of relay C, due to the closing of contact 186. -Relay C short circuits winding I of relay P at contact 440 with the result that relay P is de-energized and restores the group selector IGW as well as the additional impulse receivers IIGW and LW to normal, in a manner of no interest in the present case. The existing connection is accordirdigly cut off after the elapse of a definite per1o In order to advise the subscriber of the expected disconnection, a busy signal may be sent out from the time switch when set to the penultimate contact.

If, however, the subscriber is engaged in a call which requires considerably longer time to be completed than ordinary calls, that is to say, for example, a toll call, this connection should not be cut off. The individual operations are then as follows:

By depressing the key T1, an operator at the operators position FP seizes a toll final selector FLW and thereby causes relay C1 to be energized over: earth, key T1, off-normal contact 47701 of the toll final selector FLW, winding II of relay C1, battery, earth. Relay C1, by the closing of contact 4601, prepares a locking circuit for the further formation of the connecting route. When the 0 erator transmits impulses for the setting 0 the toll final selctor, relay A1 is intermittently energized in the following circuit due to the actuation of the key T2 during the first impulse series: earth, battery, relay Al, key T2, earth. The vertical magnet of the toll final selector FLW is accordingly intermittently actuated over :earth, battery, vertical magnet H, rotary ofi-normal contact 50'w1 of the toll final selector FLW, contact 521, winding II of relay V1, contact 48a1, earth. Relay V1 also is energized in this circuit and remains energized during the impulse series due to the short circuit of winding I. Relay V1 releases at the end of the impulse series and causes relay U to be energized in the circuit extending over the ofi-normal contact 59701 which has been closed in the meantime: earth, off-normal contact 59k1, contacts 58 211, 5701, winding III of relay U, rotary ofi-normal con tact 50101 of the toll final selector FLW, vertical magnet H, battery, earth. The vertical magnet H is not energized in this circuit. The closing of contact 51u switches over the rotary magnet D of the toll final selector FLW so that the succeeding impulse series actuates this rotary magnet and causes it'to be set to the required contact. This impulse circuit extends over: earth, batte rotary magnet D, contacts 55 21, 5110, windin II of relay V1, contact 48a1, earth. Relay 1 remains energized during the impulse series a completed: earth, contacts also in this circuit but releases at the end of said impulse series. Relay U, however, being a slow-acting relay remains energized an extended period .due to being maintained during the impulse output over: earth, contacts 6801, 672a, 6601, winding I of relay U, battery, earth. The following test circuit is now 6801, 6720, 651:1, windings II and I of rela P1, c-wiper of the toll-final selector FL c-wiper of the preselector VW, windings I and II of relay T, d-wiper of the preselector VW, battery, earth. Relays P1 and T are energized in this circuit. By the closing of contact p1, relay P1 places its winding I in a locking circuit as contact 67a is now open due to the release of relay U. Relay V1 is re-energized by a five-second switch over its winding III in the following circuit: earth, batter rotary magnet D, contacts 56121, 623 win ing III of relay V1, contact 6414, five-second switch, earth. On each energization of relay V1 the ringing machine RM is connected up to a speaking lead over contact 7 31:1 and, due to the speaking leads being switched through at contacts" 74721 and p1, causes the bell at the sub- -scribers station Tnl to operate.

When the subscriber answers, relay Y is energized over the subscribers line loop and, by opening its contact 62y, prevents a fresh energization of relay V1. At the same time, however, a locking circuit for relay P1 is closed at contact 63y over: earth, batteiigzrotary magnet D of the toll final selector W contacts 56p1, 63y, winding III of relay P1, key T1 at the operators position F p, earth. The rotary magnet D is not energized in this circuit and relay P1 remains energized.

Relay B0 is re-energized on the energiza-. tion of relay T in a similar. manner over contact 142i and, by closing its contact 1160, connects up the switch magnet TS, of the time switch, to the contact of the 15-second switch. The time switch is advanced in the manner described above and on reaching the last contact applies an earth potential over the offnormal contacts 51 023 and 81023. A toll call being involved in the present instance, this earth potential does not cause the release of the existing connection. Applying earth potential at contact 87023, however, short circuits windings II of relay Y but this relay still remains energized over its winding I and the short circuit of winding I of relay P1 at the cit-normal contact 57023, which b would release the switch in ordinary calls, has no influence in this case due to relay P1 remaining' energized over its winding III, even said device responsive to the tion and return to its original position.

The disconnection only takes place when the subscriber has finished the toll call. I The release of the connection is carried out by the operator at the toll operators position in a manner of no interest in this case.

What is claimed is:

1. In a telephone system, a subscribers line, a timing device individual to the line, means for establishing two classes of connections withthe line, and means controlled by the timing device for automatically releasing connections of one class after a predetermined time but not connections of the other class.

2. In a tele hone system, a line, a timing device indivi ual to the line, means for establishing incoming or outgoing connections of one class with the line, means for establishmg incoming connections of a different class with the line, and means controlled by said timing device for releasing either incoming or outgoing connections of said one class after a pre etermined time but not incoming connections of said different class.

3, In a telephone system, a line, a timing device associated with the line, means for establishing local and toll connections with the line, means for initiating the operation of said device responsive to the establishment of a connection, and means controlled by said devlce for releasing the connection after a predetermined time provided the connection is a local one.

4. In a telephone system, a line, a timing device associated with the hue, means for establishing local and toll connections with the line, means for initiating the operation of establishment o: E a connection, means controlled by said device for applying a potential to one conductor of the line after a predetermined time, and

means responsive to said otential for releasing the connection provlded the same is a local one.

5. In a telephone system, a line, a timing device associated with the line, an automatic switch, means including said switch for establishing a connection with said line, a control relay in the switch energized to maintain the connection, and means controlled by said device for deenergizing said relay after a predetermined time.

6. In a telephone system, a line comprising two talking conductors, a branch of said line comprising two talking conductors and a test conductor, a timing device associated with the line, means for establishing outgoing connections from the line independent of said ranch, means for establishing incoming connections to the line over said branch, and means controlled by said device for applying a potential to one of the talking conductors of the line and to said test conductor to release either type of connection.

7. In a telephone s stem, a line, a timing device individual to t e line, a branch of the 5 line comprising two talkingconductors and a test conductor, means for establishing connections of two classes with the line over said branch, means including said device for appljing a potential to said test conductor a l predetermined time after the connection is established, and means operative provided the connection is of one class for releasing the connection responsive to said application of otential.

witness whereof, I hereunto subscribe my name this 1st day of March, 1932.

MAXIMILIAN MATHIAS. 

